Most brake control systems used in the train industry today are electropneumatic in nature. These electropneumatic brake control systems consist of pneumatic and electropneumatic components and other related mechanical apparatus controlled by a centrally located electronic brake control unit. Though electropneumatic brake control systems feature the electronic brake control unit, the brakes of trains so equipped are still applied and release pneumatically via brake cylinder control valves and brake cylinders. Entirely electronic brake control systems, however, should eventually be developed. These will control electrical brake components such as electrical motors that will apply and release the train brakes electrically without the need of pneumatic backup systems.
It is well known that electronic systems are generally capable of processing and responding more quickly to a greater variety of input parameters than equivalent, though outmoded, mechanical systems. Electronic systems also typically require less physical space to implement than the bulky mechanical hardware that they replace. This factor yields a reduction in weight and an increase in available space thereby making trains so equipped more fuel efficient and capable of transporting more cargo and passengers. Electronic systems also exhibit greater reliability and thus require less physical maintenance than mechanically implemented systems.
A typical train includes at least one locomotive, one or more rail vehicles and a plurality of trainlines. The trainlines include both pneumatic and electrical lines which generally run from a head of train locomotive to a last rail vehicle in the train. These pneumatic and electrical trainlines connect to pneumatically controlled brakes and electrical devices, respectively, in each of the rail vehicles. In a locomotive, the pneumatic trainlines include an actuating pipe, a main reservoir equalizing (MER) pipe, and an independent application and release (IAR) pipe. Within a locomotive consist (i.e., two or more locomotives interconnected), each of the MER, actuating and IAR pipes respectively interconnect with the MER, actuating and IAR pipes of the other locomotives. These are the pipes that serve to supply air to each of the pneumatically controlled brake components situated on each of the locomotives.
The pneumatic trainlines also include a brake pipe whose pressure mimics pressure within a storage tank called an equalization reservoir. The brake pipe consists of a series of individual pipes interconnected serially. Usually secured to the underside of each rail vehicle, each individual pipe is interconnected to another such individual pipe via a flexible coupler situated between each rail vehicle. Connected to the equalization reservoir, the brake pipe is thus one long continuous pipe run from the head of train locomotive to the last rail vehicle. It is the brake pipe that connects and supplies air to each of the pneumatically controlled brake components situated on each of the rail vehicles.
The electrical trainlines generally include a power line, a return line and various control lines along with any number of other electrical lines. As with the brake pipe, each electrical trainline actually constitutes a series of individual wires interconnected serially. Typically secured to the underside of each rail vehicle within a separate protective conduit, each individual wire is interconnected to another individual wire to which it corresponds via a connector situated between each rail vehicle to form one of the electrical trainlines of the train. These separate protective conduits are thus interconnected serially to form a protective cable that runs from the head of train locomotive to the last rail vehicle. Though actually formed from a series of interconnected protective conduits, this protective cable is often itself referred to as "the electrical trainline" even though it actually houses multiple electrical trainlines.
The typical locomotive has an electropneumatic brake control system such as WABCO EPIC.RTM. Brake Equipment. Such a brake control system generally includes an electronic brake control unit for controlling overall operation of the brakes; a cab station unit for providing various inputs to the brake control unit including the positions of the automatic and independent brake handles through which to control the brakes on the entire train and the locomotive(s), respectively; a keyboard for accessing the brake equipment including providing certain set-up parameters; a display for monitoring brake equipment operation; a locomotive interface unit for connecting both electrical power and the electrical trainlines to the brake equipment; and a pneumatic operating unit having solenoid valves for controlling pressures in the pneumatic trainlines and in the reservoirs so as to control the brakes pneumatically according to commands received from the brake control unit.
These electropneumatic brake control systems are designed so that failure of any one of the pneumatic interconnections between any of the rail vehicles (or any other failure causing a loss of pressure in the pneumatic pipes) guarantees an emergency application of the brakes on all the vehicles of the train. Such electronic control of pneumatic braking componentry as well as the pneumatic componentry itself has proven quite dependable. Consequently, emergency brake applications occur quite infrequently given the reliability of current electropneumatic brake control systems and their associated pneumatic componentry and interconnections.
One of the foremost technical obstacles to overcome in the development of a completely electronically controlled brake system is the need for a reliable system for electrically interconnecting each of the aforementioned electrical brake components that will be situated on each of the rail vehicles. In such a system, a brake control cable containing one or more electrical lines will be used to transmit brake control signals from the brake control unit to each of the electrical brake components on each of the rail vehicles.
The brake control cable will run from the head of train locomotive to the last rail vehicle in the train. Analogous to the segmented brake pipe of contemporary electropneumatic brake control systems, the brake control cable will consist of a series of individual electrical conduits. Secured to the underside of each rail vehicle, each individual conduit will be interconnected to another individual conduit via a connector device situated between each rail vehicle to form the brake control cable. Originating in the brake control unit, these control signals will be used to command the electrical brake components to apply and release the train brakes electrically. If implemented on a freight train, which often consists of one hundred or so rail vehicles, such a completely electronic system would require as many connectors, especially if a one line brake control system is envisioned. The completely electronic system could even require double as many connectors or more depending on the design of the brake control conduit; two connectors, for example, could be employed to interconnect the rail vehicles in a two line system. Failure of the electrical connections between just one pair of adjacently disposed rail vehicles in such a system would give rise to an emergency brake application, a prospect that both train operator and customer fervently hope to avoid. Thus, the reliability of the electrical connectors in an entirely electronic brake control system is of paramount importance.
Many individuals in the railway industry contend that a completely electronically controlled brake system would be neither sufficiently reliable nor economically feasible when compared to contemporary electropneumatic brake control systems. The likelihood of connector failures in a completely electronic brake control system is said to be too great. This persuades some that brake control systems will always require some pneumatic componentry as back up to whatever type of electronics that would be employed in such a system.
The present invention addresses the aforementioned obstacles to the development of a completely electronic brake control system. Akin to the couplers used to interconnect the individual pipes serially to form the brake pipe of contemporary electropneumatic brake control systems, the present invention provides a dual connection system for interconnecting the electronic brake components between each of the rail vehicles so as to form one variant of the aforementioned brake control cable. Featuring a pair of electrical paths for each line to be interconnected between rail vehicles and a means of testing the integrity of same, the present invention will provide highly reliable electrical connections for use with the entirely electronic brake control systems of the future. It should be apparent after reading this document that the present invention could also be adapted to any number of other electrical applications, even those unrelated to railway industry applications. Obvious modifications may be necessary, though, depending upon the specific application in which the present invention is employed.
It should be noted that the foregoing background information is provided to assist the reader in understanding the present invention. Accordingly, any terms used herein are not intended to be limited to any particular narrow interpretation unless specifically stated otherwise in this document.